1 88 Natural Theology. 



The quartz pebble, and almost all the gems, bor- 

 -row their hardness and varied tints from combina- 

 tions of this same element. The sand that smooths 

 the rugged rocks, and a large proportion of all the 

 salts upon which plant life is dependant, are oxides. 

 Remove the oxygen from our globe, and it'would be 

 left a metallic ball, mingled only here and there with 

 metalloids in combination. Then eight-ninths of 

 all the waters that fill the oceans, roll down in mighty 

 rivers, and permeate the earth, is oxygen. Thus far 

 it appears in combination. 



It has seized upon the metals and turned them to 

 stone ; on hydrogen, and formed the waters. In no 

 one of these substances would its presence ever be 

 suspected, were it not for that searching analysis 

 by which the chemist unlocks every element from 

 the chains with which its own affinity has bound it. 



But in the air we have it uncombined. It is dilut- 

 ed with four times its quantity of nitrogen ; but 

 there is no chemical union between them, and the 

 oxygen is unchanged. 



No chemist can study the rocks without feeling 

 that there was a time when their particles were 

 brought together to form the compounds which they 

 now present. The oxygen that forms the granite 

 was undoubtedly once free and uncombined, and the 

 oceans of water once floated in space as separate 

 gases. But when the great experiment was made 

 of bringing these elements together ; when the com- 

 pounds of the rocks and the waters of the oceans 

 had been formed ; when oxygen had spent its fury 



